1. Field of the Invention
This invention is in the field of multiple tone generators and more particularly to a siren having multiple sound modes.
2. Description of the Prior Art
Siren circuits are known to the art. Circuits having multiple sound modes have become prevalent, especially in recent years, in law enforcement and emergency vehicles. It has been found that by changing the sound from one mode to another, that motorist's attention can more reliably be gained. Therefore, circuits having a "high-low", "wail", and "yelp" sound modes have been employed. The circuitry employed in such systems to obtain the three sound modes has been relatively complex and expensive to manufacture, having many individual components, which resulted in attendant increased maintenance due to component failure or wiring and connection failure between components. In addition, the container required to house such components was necessarily relatively bulky in size and heavy in weight, further limiting the applications and making the device less convenient to use.